Many electric motors used in industrial and commercial processes and buildings are controlled by soft starter equipment. Soft starters are used to start a motor and stop a motor in a desired manner, such as to eliminate electrical surges in the electrical supply and/or overheating in the motor. Soft starters are also used to reduce or eliminate mechanical shocks or vibration which might otherwise occur under start/stop conditions causing wear and damage to the pumps, fans etc. driven by the motors. A soft starter typically measures the input current and/or voltage of the motor and regulates the input current and/or voltage received by the motor to achieve a desired start or stop performance.
The soft starter generally requires configuration to suit the circumstances of each application. During configuration the parameters influencing in particular the starting current, and also factors such as the speed, start up time or maximum input current etc. have to be selected or set up in the soft starter according to what kind of start or stop is desired for the motor and/or the equipment it is driving. Soft starters may comprise many features and functions and the configuration is often therefore somewhat difficult and time consuming.
Although AC motors are used all over the world, the AC supply frequency may be either 50 Hz or 60 Hz and the range of operating currents and operating voltages supplied is extensive. Protection against overheating of the semiconductor components is necessary as well as other types of overload protection. In summary, there usually are a great number of factors or parameters that require configuration or selection in order to be able to use a soft starter.
Soft starters are well known in general industrial practice, see for example, EP 1 037 373 A2, entitled “Command module for motor control system”.
One type of soft starter, available from the Danfoss company, model MCD 3000, comprises a display where an operator or technician may read information about various functions. Associated with the display is a series of buttons with which the operator may select particular functions or features to be checked and/or configured. The buttons are each marked with a pictorial symbol representative of certain functions. However, the display also includes coded names for functions, which may be difficult for an operator to interpret correctly. In addition, a difficulty with this type of design is that the operator must recognise the meaning of the symbols correctly in order to be able to configure and/or operate the soft starter efficiently. This requires extensive customer support, beginning with comprehensive user manuals in order to configure such a soft starter correctly.